The P-class "Panzerschiffe" (armored ships) were an unrealized project intended to succeed the famous Deutschland-class "pocket battleships." These ships were envisioned as fast, heavily armed, and relatively well-armored commerce raiders, capable of outgunning cruisers and outrunning battleships. They were to displace around 20,000–25,000 tons and carry 11-inch guns, with a top speed of approximately 34 knots.
Their role would have been similar to earlier German raiders: disrupt Allied shipping lines and evade major fleet units. However, they would have been more capable than their predecessors in terms of speed and firepower.
How the USN Might Have Countered Them
Use of Aircraft Carriers The USN's reliance on aircraft carriers would have been its primary countermeasure. By the time the P-class could realistically have been completed (mid-to-late 1940s), carriers and their air groups had become the dominant naval force. US carrier-based aircraft like the F6F Hellcat and TBF Avenger could easily detect and destroy P-class raiders before they could pose a significant threat. Naval air power was particularly effective at hunting down raiders, as demonstrated by the sinking of ships like the Bismarck and Tirpitz.
Escorts and Patrol Forces The USN would have continued deploying heavily armed cruiser task forces and convoy escorts to hunt down commerce raiders. Heavy cruisers like the Baltimore class, armed with 8-inch guns, were already more than a match for the P-class. Additionally, a network of destroyers, patrol aircraft, and radar-equipped ships would have been used to locate and engage such raiders.
Alaska-class Cruisers The Alaska-class large cruisers, with their 12-inch guns, were designed specifically to counter "super cruisers" or heavily armed commerce raiders like the Japanese Tone-class or the projected P-class. While only two ships (Alaska and Guam) were completed, their design philosophy made them ideal for combating P-class ships. If the P-class had been constructed and posed a significant threat, the USN might have built additional Alaska-class ships to deal with them. However, their high cost, limited utility in fleet engagements, and vulnerability to aircraft would have been significant drawbacks.
Submarines US submarines proved exceptionally effective at sinking enemy shipping and warships during World War II. P-class ships, which would likely have operated independently or in small groups, would have been highly vulnerable to submarine attacks while cruising the open seas.
Battleships Although overkill, battleships like those of the North Carolina or South Dakota classes could have easily overwhelmed P-class raiders in a direct confrontation. However, the slow speed and limited range of battleships made them less suited for chasing down fast commerce raiders.
Why More Alaska-class Cruisers Might Not Be Built
While the Alaskas were theoretically an ideal counter to ships like the P-class, the USN's focus on carriers and the declining importance of surface raiders in naval strategy by the mid-1940s made large cruiser programs less of a priority. The existing Baltimore-class heavy cruisers and carriers were already sufficient to neutralize the P-class threat without significant additional investment in specialized ships.